Photochromic spirooxazine polysiloxanes

ABSTRACT

Polysiloxane copolymers containing both photochromic and lightstabilizing groups with enhanced UV-fatigue resistance can be used as coatings for devices with variable optical density, including lenses, glazing, textiles and the like, to provide light-sensitive darkening effects. The photochromic groups are spironaphtooxazine groups and the lightstabilizing groups are hindered amine light stabilizing (HALS) groups.

FIELD OF THE INVENTION

The present invention relates to photochromic compounds and morespecifically to polysiloxane copolymers containing both photochromic andlightstabilizing groups with enhanced UV-fatigue resistance, which canbe used as coatings for devices with variable optical density, includinglenses, glazing, textiles and the like to provide light-sensitivedarkening effects.

BACKGROUND OF THE INVENTION

Photochromic polymers, that is, polymers which contain photochromicgroups in a macromolecule, are materials of significant technologicalpotential in many industrial fields. For example, such polymers can beused in the manufacture of the plastic material of eye lenses and themanufacture of windows for the automobile industry.

Spirooxazines and their use in photochromic lenses have been recentlyreviewed by Crano et al., 1992. There has also been a significant amountof research reported on a number of side-chain photochromic polymers inwhich photochromic spiropyran or spirooxazine side groups are attachedto a main chain through a flexible spacer (Krongauz, 1990, 1992). Thestructure of these compounds allows incorporation of a very high contentof a photochrome in a polymer which can reach 100%. That is, eachstructural unit of the polymer contains the photochromic group.Properties of such polymers can be substantially different from theproperties of the polymers containing photochromic molecules as solute,as photochromic compounds have been usually employed in photochromiclenses. Such solutions in polymers have inherent restrictions insolubility of the photochromic compound.

U.S. Pat. No. 5,322,945 (Krongauz et al.), assigned to the presentapplicants, describes spirooxazine photochromic polysiloxanes having anadvantage over other spirooxazine photochromic compounds by giving highquality coatings for plastic lenses. However, these photochromicpolysiloxane coatings exhibit rather low fatigue resistance againstillumination with light.

European Patent EP 162524 describes organic polymer stabilizingcompounds, which are derivatives of 2,2,6,6-tetramethylpiperidine,2,2,6,6-tetramethylmorpholine or of 2,2,3,5,5-pentamethylpyrrolidinecarrying a silyl group, which is capable of being hydrolyzed to silanoland is bonded to the ring structure by an Si--C bond. These compoundscontain a sterically-hindered amino group together with a hydrolyzablesilyl group, and are said to be able to stabilize organic polymers ingeneral, and in particular homopolymers and copolymers of olefins anddiolefins, such as polypropylene, polybutadiene and polyethylene of highand low density, especially towards ultraviolet radiation.

The reactive stabilizing compounds can give rise to resinificationreactions, or can be anchored to a support or to the polymer to bestabilized, these characteristics enhancing the permanence of thestabilizer in the polymer.

The present inventors have tried to add the stabilizing compoundsdescribed in EP 162524 to photochromic polysiloxanes, particularly thosedescribed in U.S. Pat. No. 5,322,945. However, the maximum amount ofsuch stabilizing compounds that could be added to the photochromicpolysiloxanes without phase separation was less than 1% in relation tothe polysiloxanes, such mixtures not giving any detectable protectionagainst fatigue.

It would be highly desirable to provide new photochromic polysiloxanepolymers that give high quality coatings for plastic lenses and give asignificant protection against fatigue produced by light.

SUMMARY OF THE INVENTION

In accordance with the present invention, photochromic polysiloxanecopolymers have been produced that contain both photochromicspironaphthooxazine and hindered amine light stabilizing (HALS) groupsincorporated in polysiloxanes through a hydrocarbon spacer. These HALSgroups include radicals derived from 2,2,6,6-tetramethylpiperidine,2,2,6,6-tetramethylmorpholine and 2,2,3,5,5-pentamethylpyrrolidine.Other side groups required for promoting the polymer synthesis and/orimproving physical and chemical properties of the polymers (viscosity,curing ability, etc.) may also be introduced into the copolymers.

The present invention thus provides a photochromic polysiloxaneincluding functional moieties of the formula: ##STR1## and optionallymoieties of the formula: ##STR2## wherein R" is a C₁ -C₁₅ alkyl; R'" isH, OH, C₃ -C₁₅ alkyl, or C₃ -C₁₅ alkyl substituted by C₁ -C₂ alkoxy,phenyl, naphthyl and phenyl substituted by one or more C₁ -C₄ alkyland/or OH; G is a photochromic radical derived from a compound whereinsaid compound is a photochromic compound of the formula I: ##STR3##wherein R₁ is selected from the group consisting of (A) hydrogen, C₁ -C₆alkyl, phenyl, or C₁ -C₆ alkyl substituted by halogen, hydroxy, methoxy,carboxyl, methoxycarbonyl, phenyl or diphenyl; and (B) --(CH₂--)n--CH=CH₂ wherein n is an integer from 1 to 20; when R₁ is (B), thenR₂ through R₈ are each selected from the group consisting of hydrogen,C₁ -C₆ alkyl, methoxy, hydroxy, phenyl, phenyl-carbonyloxy, phenyl(C₁-C₆)alkyl carbonyloxy, di(C₁ -C₆)alkylamino, (C₁ -C₆)alkylphenylamino,piperidino, indolino and tetrahydroquinolino; when R₁ is (A), then oneof R₂ through R₈ are (C)--X--(CH₂ --)n--CH=CH₂, wherein n is an integerfrom 1 to 20 and X is selected from the group consisting of a covalentbond, O, N--R' (wherein R' is H or C₁ -C₆ alkyl), CO--O, CO--NH, and--CH=N and the remaining ones of R₂ through R₈ are selected from thegroup consisting of hydrogen, C₁ -C₆ alkyl, methoxy, hydroxy, phenyl,phenylcarbonyloxy, phenyl(C₁ -C₆)alkyl carbonyloxy, di(C₁-C₆)alkylamino, (C₁ -C₆) alkylphenylamino, piperidino, indolino andtetrahydroquinolino, said radical (CH₂)_(n+2) G being covalently bondedthrough the alkene carbon of radical R₁ as moiety (B) or of R₂ throughR₈ as moiety (C); and U is a radical derived from a compound selectedfrom a compound of the formulas II-IV herein: ##STR4## where m is aninteger from 1 to 20, said radical (CH₂)_(m+2) U being covalently bondedthrough the alkene carbon atom; and the polysiloxanes being cyclic orlinear including terminal groups of the formulas (R")₃ --Si--,covalently bonded to the Si atom of an Si--O! moiety and Si--(R")₃covalently bonded to the O atom of an Si--O! moiety. R" is preferablymethyl and R'" is preferably C₃ -C₇ alkyl, more preferably heptyl, or C₃-C₄ alkyl substituted by phenyl substituted by one or more C₁ -C₄ alkyland/or OH, more preferably a 4-hydroxy-3,4-di(t-butyl)phenyl radical.The invention further provides coated articles, particularly coatedlenses, comprising a substrate, e.g., a lens substrate, coated with aphotochromic polysiloxane of the invention. The copolymers and theirblends are coated on the plastic lens surface and the film is cured byheating. A second scratch resistance layer can be coated to improvemechanical properties of the film and can also be cured by heating. Thephotochromic properties of the films, especially photo-fatigueresistance of the photochromic copolymers are substantially better thanthose of the films based on the polymers that do not include the HALSgroup.

BRIEF DESCRIPTION OF THE FIGURES

Other advantages of the present invention will be readily appreciated asthe same becomes better understood by reference to the followingdetailed description when considered in connection with the accompanyingdrawings wherein:

FIG. 1 shows infrared (IR) spectra of the initial reaction mixture(curve 1) and of the linear copolymer (curve 2) prepared fromspironaphthooxazine (compound Ia ) and HALS (compound (II), ration 1:1,according to Example 1, obtained after 36 h heating at 80° C.; the Si--Habsorption band at 2140 cm⁻¹ disappears.

FIG. 2. shows NMR spectra of the copolymers prepared from the feedsaccording to Example 1 with different spironapthooxazine (compoundIa)/HALS (compound II) ratios: (1) 9:1; (2) 7:3; (3) 1:1. Theintegration indicates a proportional increase of the HALS concentrationin the copolymers.

FIG. 3 shows IR spectra of the initial reaction mixture (1) and of thelinear triple polysiloxane copolymer (2) obtained fromspironaphthooxazine Ia, HALS II and heptene, ratio 6:3:1, according toExample 2, after completion of the reaction (36 h, heating 80° C.).

FIG. 4 shows NMR spectrum of the triple polysiloxane copolymer accordingto Example 2, prepared from spironaphthooxazine Ia, HALS II and heptene,ratio 6:3:1.

FIGS. 5A and 5B show spectra of the polysiloxane copolymer prepared fromspironapthooxazine Ia/HALS II, ratio 1:1, according to Example 1,irradiated with UV light at different stages of thermal color decay. Thespectra were recorded at 1 min intervals: (FIG. 5A) The non-cured film(τ_(1/2) =1.5 min); (FIG. 5B) The film cured by heating at 85° C. during1 hr (τ_(1/2) =12 min) (Example 6) (t=+27° C.).

FIG. 6 shows kinetics of the color decay of UV-irradiated films of thephotochromic polysiloxanes of Example 1 with the following copolymercompositions: spironapthooxazine Ia HALS II: (1) 9:1 (τ_(1/2) >30 min);(2) 7:3 (τ_(1/2) =10 min); (3) 1:1 (τ_(1/2) =1.5 min). The curve (4)relates to the triple spironaphthooxazine Ia/HALS II/heptane copolymer6:3:1 of Example 2 (τ_(l/2) >30 min) (Example 6) (t=+27° C.).

FIG. 7 shows spectra and color decay of UV-irradiated films of thetriple polysiloxane copolymer prepared from spironaphthooxazine(compound Ib)/ HALS II/heptane, ratio 6:3:1, according to Example 2(τ_(1/2) =3.5 min) (t=+10° C.).

FIG. 8 shows change of the steady-state optical density of the copolymerfilms after irradiation with non-filtered light of a medium pressuremercury lamp. (1) Polysiloxane homopolymer with 100% spirooxazine(compound Ia) substitution; (2) Copolymer spironaphthooxazineIa/heptane, 6:4; (3) Copolymer spironaphthooxazine Ia/HALS II/heptane,6:3:1 of Example 2.

FIG. 9 shows change of the steady-state optical density of photochromiccopolymers with spironaphthooxazine (compound Ib) after irradiation withnonfiltered light of a medium pressure mercury lamp. (1) Polysiloxanecopolymer spironaphthooxazine Ib/heptane, 6:4; (2) Copolymerspironaphthooxazine Ib/ HALS II/heptane, 6:3:1 of Example 2.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides photochromic polysiloxane copolymersincluding siloxane functional moieties having both a photochromicmonomer and a light stabilizer of the hindered amine type, hereinreferred to as a HALS monomer, covalently bound thereto.

The photochromic monomers used in the present invention are those of thegeneral formula (I) herein. Some of them have been described in U.S.Pat. No. 5,322,945, herein incorporated in its entirety by reference.

The above-described photochromic monomer of formula I is characterizedby including a linker arm selected from (B) --(CH₂ --)n--CH=CH₂extending from the indoline nitrogen as the R₁ group, and (C) --X--(CH₂--)n--CH=CH₂ when the linker arm extends from a phenyl carbon as ingroups R₄ to R₈ or an indoline carbon as in groups R₂ and R₃.

The chemical differences between these two groups are due to the natureof the synthetic reactions used to assemble the photochromic compound asdiscussed below. In either case, an alkene linker arm extends fromeither the indole nitrogen or carbon or a phenyl carbon, the linker armhaving a length of 3 to 22 carbons.

The number of carbons in the linker arm is significant with regard tothe efficiency of the addition reaction to the polymer as it is known inthe art.

Each photochromic monomer includes a single linker arm as groups R₁through R₈, the remaining groups being various functionalities asdefined above. These functionalities can be synthesized by chemicalreactions known in the art, for example as described in U.S. Pat. No.5,322,945 and in Crano et al., 1992.

Examples of photochromic monomers used in the present invention arethose of formulas Ia, Ib and Ic as follows: ##STR5##

wherein in formulas Ib and Ic, R₁, R₄ and R₅ are H or lower alkyl,preferably methyl.

The compound of formula Ia has been described in U.S. Pat. No.5,322,945. The compounds Ib and Ic are novel monomers and are part ofthe present invention.

HALS monomers used in the present invention are the derivatives of2,2,6,6-tetramethylpiperidine, 2,2,6,6-tetramethylmorpholine and2,2,3,5,5-penta-methylpyrrolidine of formulas II, III and IV herein,respectively. The preparation of these compounds is described in EP162524.

In one embodiment, the invention comprises a random linear polysiloxaneof the formula: ##STR6##

wherein x, y and z are integers, the sum of which k is an integer of atleast 4, x can be equal to zero, and n and m are integers of 1 through20, and R", R'", G and U are as defined before. In one example, k is 80,y and z being 39 and x=2, n=4 and m=3.

In another embodiment, the invention provides a cyclic polysiloxanehaving the formula: ##STR7##

wherein k, x, y, z, n, m, R", R'", G and U are as defined above. In oneexample, k is 4.

The values of k=x+y+z are inherent properties derived from commerciallyavailable siloxane polymers. Hence, since the values of k are not at allrate limiting on the synthetic reactions of the invention and there isno relative limit on the values of k as conventional siloxane polymersare derived, the only limitation is their lower value and that they areintegers.

The invention further relates to a method for the preparation of thefatigue resistant photochromic polysiloxane copolymers of the inventioncontaining both spironaphthooxazine photochromic groups and HALS groupsconnected to the main chain through a flexible alkyl linker arm, whichcomprises adding a photochromic spironaphthooxazine monomer of formula Iherein containing an alkene terminated side-chain and a HALS monomerincluding an alkene terminated side-chain of formula II, III or IVherein to an Si--H-containing polymer, wherein the photochromicspironaphthooxazine and HALS groups will bind covalently through thealkene carbon to SiH! moieties of the siloxane polymer. The reaction ispreferably carried out in the presence of a metal-containing catalyst,most preferably a Pt-containing catalyst. The reaction proceeds to ahigh degree of completion of about 100% substitution.

An advantage of the polysiloxane copolymers of the present invention ascompared, for example, to the prior art polysiloxanes described in U.S.Pat. No. 5,322,945 is a very high protection of the photochromic groupsfrom UV irradiation degradation due to the statistical distribution ofthe spironaphthooxazine and HALS side groups in the macromolecule, thusimparting substantially higher photochromic stability to thepolysiloxane polymers.

Even at a high concentration of the HALS groups there is no phaseseparation and they are in very close proximity to the photochromicgroups. The polymers can be easily cured on a polymer surface by mildheating, forming a transparent film, whose rigidity depends on arelative content of different side groups in a macromolecule, which alsostrongly affects the kinetics of the photochromic reactions.

EXPERIMENTAL SECTION

The invention will now be illustrated by the following examples, towhich it is not limited.

In these examples, the following chemicals were used without furtherpurification: 2,3,3-trimethylindoline (Aldrich), allyl iodide (BDH),6-bromo-1-hexene (Fluka), 1-nitroso-2-naphthol, 98% (Aldrich),2,2,6,6-tetramethyl-4-piperidinol, 98% (Aldrich),1,2-naphthoquinone-4-sulfonic acid potassium salt, 90% (Aldrich),piperidine (BDH). The polymers used are: poly(methylhydrosiloxane),degree of polymerization (DP)=35 (Merck) and DP=80 (ABCR), tetra- andpenta(methylhydrosiloxane) (ABCR).

Example 1.

Preparation of Photochromic Linear Polysiloxane Copolymers withSpironaphthooxazine and Tetramethylpiperidine Side Groups. 300 ml (0.76mmol) of the spironaphthooxazine derivative (compound Ia, n=4), 150 mg(0.76 mmol) of the tetramethylpiperidine derivative (compound II, n=1)and 92 mg (1.52 mmol) of linear poly(methylhydrosiloxane), DP=80 (ABCR)and 0.23 mg of Pt(C₁₀ H₁₂)Cl₂ were dissolved in dry toluene. The flaskwas sealed and kept for 36 hours at 80° C. until the Si-H absorptionband at 2140 cm⁻¹ had practically disappeared (FIG. 1). The polymer wasprecipitated by methanol and freeze-dried from benzene under highvacuum. Analysis of the UV-visible electronic spectra of the copolymer,according to Zelichenok et al. Macromolecules 25, 3179-3183 (1992)indicates that the copolymer contains photochromic and HALS groups in aratio of 1:1 (not shown).

The spironaphthooxazine compound Ia was prepared as described in U.S.Pat. No. 5,322,945 and the tetramethylpiperidine compound II wasprepared as described in EP 162524.

The same procedure was applied for the preparation of copolymers withother relative contents of the spironaphthooxazine Ia and HALS II sidegroups (9:1 and 7:3). Analysis of the UV-visible electronic spectra ofthe copolymers indicated that the ratio of spironaphthooxazine/HALS sidegroups in the copolymers coincides with the corresponding monomers inthe feed (not shown). This is also illustrated in FIG. 2 by the NMRspectra of the three copolymers prepared from the feeds with 9:1 (curve1), 7:3 (curve 2) and 1:1 (curve 3) spironaphthooxazine/HALS ratios.

A similar procedure was used for preparing copolymers containing otherspironaphthooxazine side groups, for example, copolymers containing the6'-piperidino-substituted spironaphthooxazine compound of formula Ibherein and the HALS monomer II, ration 1:1. The synthesis of the novelcompound Ia is described in Example 4 herein.

Example 2.

Preparation of Photochromic Linear Polysiloxane Triple Copolymers withSpironaphthooxazine, Tetramethylpiperidine and Heptane Side Groups. 500mg (1.26 mmol) of spironaphthooxazine derivative (compound Ia, n=4), 124mg (0.63 mmol) of HALS (compound II, n=1), 21 mg (0.21 mmol) of heptene,126 mg (2.1 mmol) of linear poly(methylhydrosiloxane), DP=80 (ABCR), and0.35 mg Pt(C₁₀ H₁₂)Cl₂ were treated as described in Example 1.Completion of the reaction is shown by IR and NMR spectra depicted inFIGS. 3 and 4, respectively. The spirooxazine Ia/ HALS II/heptane ratioin the copolymer was 6:3:1, as it was in the feed. Other R'" sidegroups, such as alkyl substituted by aryl or alkoxy etc. can beincorporated in the polysiloxane copolymers in a similar way.

By the same procedure, a triple polysiloxane copolymer was prepared fromspironaphthooxazine compound Ib, HALS II and heptene, in the ratio6:3:1.

Example 3.

Preparation of Photochromic Cyclic Copolymer (K=40). 150 mg (0.38 mmol)of the spironaphthooxazine derivative (compound Ia, n=4), 74.9 mg (0.38mmol) of HALS (compound II), ratio 1:1, 33.5 (0.76 mmol) oftetra(methylhydrosiloxane) and 0.12 mg of Pt(C₁₀ H₁₂)Cl₂ were treated asdescribed in Example 1, thus producing the cyclic copolymer.

Example 4.

Preparation of 1-(1-Hex-5-Enyl)-3,3-Dimethyl-6"-Piperidinospiro-Indoline-2.3"-3H-Naphtho 2,1-b! 1,4-Oxazine! (Compound Ib). 2.38 g(0.099 mmol) of 4-piperidino-1,2-naphthoquinone was prepared by the samemethod as is known for the preparation of4-morpholino-1,2-naphthoquinone The product was then heated under refluxwith 0.82 g, (0.119 mmol) hydroxylamine hydrochloride in the presence ofa base. The solvent was removed and the residue was dissolved inmethylenechloride, washed with brine and dried. The solvent wasevaporated to yield 4-piperidino-1,2-naphthoquinone monooxime as an oilwhich was reacted with equal amounts of1-(1-hex-5-enyl)-3,3-dimethyl-2-methylene indoline (prepared asdescribed in U.S. Pat. No. 5,322,945) in boiling trichloroethylene. Thesolvent was removed and the resulting oil chromatographed on silica togive the pure product. ¹ H NMR (400 MHz, C₆ D₆)δ: 0.93(s,6H); 1.17-1.68(m, 10H); 1.86-1.92 (m, 2H (CH₂ --CH:CH₂)); 2.80 (broad s, 4H,N(CH₂)₂)); 3.14 (m, 2H (--N--CH₂ --)); 4.98 (m, 2H (H₂ C═CH--)); 5.70(m, 1H (H₂ C═CH--)); 6.55 (d, 1H); 6.59 (s, 1H); 6.93 (t, 1H); 7.00 (m,1H); 7.19 (m, 1H); 7.36 (dt, 1H); 7.54 (dt, 1H); 7.69 (m, 1H); 8.28 (d,1H); 9.20 (d, 1H).

Example 5.

Coating of the Plastic Lens Surface With Light-Stabilized PhotochromicPolysiloxane Copolymers of the Invention.

A 50% toluene solution of the polysiloxane triple copolymer of Example 2containing 60% of the spironaphthooxazine Ia groups, 30% of the HALS IIgroups and 10% of heptane was used for plastic (CR-39) lens coating. Thelenses were coated by dipping or spinning. After drying, the lenses wereheated over 45-60 min. at 85° C., which led to a marked hardening of thecopolymer film, as a result of curing the polymer.

For additional improved mechanical properties of the films, they werecoated with a layer of a scratch-resistant coating (Rupp and Hubrach),without any marked change in transparency being observed.

Example 6.

Spectra and Color Decay Kinetics.

The absorption spectra of UV-irradiated light-stabilized photochromicpolysiloxanes containing spironaphthooxazine Ia and Hals II, accordingto Example 1, ratio 1:1, in the films, are shown in FIGS. 5A and 5B. Thetypical kinetics of decoloration processes of UV-irradiated films ofcopolymers according to Examples 1 and 2, as shown in FIGS. 6 and 7,indicate that the higher the HALS content, the faster the decay. Thecolor-decay does not obey first-order kinetics. The initial fast decayis followed by a slower one. As a first approximation, the color decaycan be described by a sum of two exponential equations with fast andslow rate constants. Therefore, for comparison of different samples, thehalf-life time parameter (τ_(1/2)) was used.

Example 7.

Photostability of the Copolymers.

Incorporation of HALS groups by covalent bonds in photochromicpolysiloxanes results in a significant increase of photochemicalstability of the copolymers. FIGS. 8 and 9 indicate that photo-inducedfatigue of the copolymers is inhibited by incorporating thetetramethylpiperidino (HALS) groups into polysiloxane. The effect isincreased with the HALS content in the copolymers.

The degradation curves, the change of optical density of color as afunction of irradiation time, have different shapes for the copolymerswith and without HALS groups. The latter have an induction period, whichis clearer for the copolymers with a high HALS concentration.

This example demonstrates the possibility of enhancing photostability ofphotochromic polysiloxanes by incorporation into a macromolecule of bothphotochromic and light-stabilizing groups. Random distribution of theside groups in a macromolecule leads to very close proximity of thesegroups and efficient light protection.

References

1. Crano J. et al. (1992) in Applied Photochromic Polymer Systems, (C.B. McArdle, ed.), Blackie & Sons, Glasgow/London pp. 31-76.

2. Krongauz, V. et al. (1990) in Photochomism: Molecules and Systems,(H. Duer and H. Bonas-Laurent, eds.), Elsevier, pp. 793-821.

3. Krongauz, V. et al. (1992) in Applied Photochromic Polymer Systems,(C. B. McArdle, ed.), Blackie & Sons, Glasgow/London pp. 121-173.

We claim:
 1. A photochromic light-stabilized polysiloxane includingfunctional moieties of the formula ##STR8## and optionally moieties ofthe formula: ##STR9## wherein R" is a C₁ -C₁₅ alkyl; R'" is H, OH, C₃-C₁₅ alkyl, or C₃ -C₁₅ alkyl substituted by C₁ -C₂ alkoxy, phenyl,naphthyl and phenyl substituted by one or more C₁ -C₄ alkyl and/or OH; Gis a photochromic radical derived from a compound wherein said compoundis a photochromic compound of the formula I: ##STR10## wherein R₁ isselected from the group consisting of (A) hydrogen, C₁ -C₆ alkyl,phenyl, or C₁ -C₆ alkyl substituted hy halogen, hydroxy, methoxy,carboxyl, methoxycarbonyl, phenyl or diphenyl; and (B)--(CH₂--)n--CH═CH₂ wherein n is an integer from 1 to 20; when R₁ is (B), thenR₂ through R₈ are each selected from the group consisting of hydrogen,C₁ -C₆ alkyl, methoxy, hydroxy, phenyl, phenylcarbonyloxy,phenyl(C1-C6)alkyl carbonyloxy, di(C1-C6)alkylamino,(C1-C6)alkylphenylamino, piperidino, indolino and tetrahydroquinolino;when R₁ is (A), then one of R₂ through R₈ are (C) --X--(CH₂--)n--CH═CH₂, wherein n is an integer from 1 to 20 and X is selectedfrom the group consisting of a covalent bond, O, N--R' (wherein R' is Hor lower alkyl), CO--O, CO--NH, and --CH═N and the remaining ones of R₂through R₈ are selected from the group consisting of hydrogen, C₁ -C₆alkyl, methoxy, hydroxy, phenyl, phenylcarbonyloxy, phenyl(C1-C6)alkylcarbonyloxy, di(C1-C6)alkylamino, (C1-C6)alkylphenylamino, piperidino,indolino and tetrahydroquinolino, said radical (CH₂)_(n+2) G beingcovalently bonded through the alkene carbon of radical R₁ as moiety (B)or of R₂ through R₈ as moiety (C); and U is a radical derived from acompound selected from a compound of the formulas II-IV herein:##STR11## where m is an integer from 1 to 20, said radical (CH₂)_(m+2) Ubeing covalently bonded through the alkene carbon atom; and thepolysiloxanes being cyclic or linear including terminal groups of theformulas (R")₃ --Si--, covalently bonded to the Si atom of an Si--O!moiety and Si--(R")₃ covalently bonded to the O atom of an Si--O!moiety.
 2. A polysiloxane of claim 1 of the formula: ##STR12## whereinx, y and z are integers, the sum of which k is an integer of at least 4,x can be equal to zero, and n and m are integers of 1 through 20, andR", R'", G and U are as defined in claim
 1. 3. A polysiloxane of claim 2wherein R" is CH₃, k=80, y=39, z=39, x=2, n=4, m=1, G is a radical##STR13## and U is a radical ##STR14##
 4. A polysiloxane of claim 2wherein R'" is heptyl, x=8, y=48, z=24, n=4, m=1, G is a radical and Uis a radical ##STR15##
 5. A polysiloxane of claim 2 wherein G is aradical R'" is heptyl, U is as defined in claim 3, x=8, y=48, z=24, n=4and m=1.
 6. A polysiloxane of claim 1 of the formula ##STR16## whereink=x+y+z is an integer of at least 4, G, U, R" and R'" are defined inclaim
 2. 7. A method for the preparation of a photochromiclight-stabilized polysiloxane as defined in claim 1, which comprisesreacting a poly(alkyl-hydrosiloxane) with a monomer derived fromphotochromic spironaphthooxazine compound I and a monomer derived fromcompound II, III or IV, wherein the radicals (CH₂)_(n+2) G derived fromcompound I and (CH₂)_(m+2) U derived from compounds II, III or IV, arelinked covalently through the alkene carbon to SiH! moieties of thepolysiloxane, thus obtaining a polysiloxane as defined in claim 1wherein R'" is H.
 8. A coated article comprising:a substrate layer, anda coating layer consisting of a polysiloxane as defined in claim
 1. 9. Acoated article comprising:a substrate layer, and a coating layerconsisting of a polysiloxane as defined in claim
 2. 10. A coated articleaccording to claim 8 further containing a coating layer withscratch-resistant properties.
 11. A coated lens comprising:a lenssubstrate coated with a polysiloxane as set forth in claim
 1. 12. Acoated article comprising:a lens substrate coated with a polysiloxane asdefined in claim
 2. 13. A coated lens according to claim 11 furthercomprising a coating layer with scratch-resistant properties.
 14. Amethod of producing a coated article according to claim 10 whichcomprises curing both the polysiloxane layer and the scratch-resistantlayer by heating.
 15. A method for the preparation of a photochromiclight-stabilized polysiloxane as defined in claim 1, which comprisesreacting a poly(alkyl-hydrosiloxane) with a monomer derived fromphotochromic spironaphthooxazine compound I; a monomer derived fromcompound II, III or IV; and an alkene monomer, wherein the radicals(CH₂)_(n+2) G derived from compound I and (CH₂)_(m+2) U derived fromcompounds II, III and IV, are linked covalently through the alkenecarbon to moieties of the polysiloxane, thus obtaining said polysiloxanewherein R'" is alkyl.